JSFiddle - React, Tailwind, and code Playground

HTML

<div class="myStyle" style="width:200px;height:300px;border:2px solid">
Inner Text
</div>

JavaScript

var style=document.createElement("style");
style.type = 'text/css';
document.body.appendChild(style);

 style.innerHTML = ".myStyle{background-color: red;}";